[Script run 2019-04-16 14:54:48]

Load data

Clean data

Sane responses fulfil all:

  • estimate (1890, 2010)

  • after <= estimate

  • before >= estimate

  • after >= 1800

  • before <= 2000

Var1 Freq
TRUE 1553
Estimate out of range 0
After out of range 0
Before out of range 0
After after estimate 0
Before before estimate 0

Participants performance

## Warning: Column `id` joining character vector and factor, coercing into
## character vector
id questionCount hitRate bracketRate goodAnswerRate meanError sdError meanBracketWidth sdBracketWidth meanRT hard_easy dull_fun tooLong_tooShort
c49507a0 c49507a0 10.00 0.30 1.00 1.00 11.50 12.03 47.20 30.11 21881.70 0.50 0.50 0.50
42057dd2 42057dd2 50.00 0.84 0.96 1.00 0.94 3.59 18.14 6.66 46364.70 0.42 0.50 0.45
c030ca6d c030ca6d 50.00 0.16 0.80 1.00 12.24 18.82 26.82 21.40 42456.60 0.18 0.74 0.50
0d739e63 0d739e63 50.00 0.16 0.78 1.00 9.20 16.49 13.42 11.22 38530.98 0.27 0.72 0.51
917ff8c7 917ff8c7 50.00 0.22 0.72 1.00 9.74 19.35 9.18 5.59 38148.84 0.31 0.70 0.37
6c343b84 6c343b84 50.00 0.08 0.64 1.00 14.46 16.51 30.74 24.58 17500.86 0.08 0.84 0.48
b0f3567b b0f3567b 50.00 0.04 0.58 1.00 18.36 17.42 30.88 18.43 26714.30 0.39 0.43 0.33
5f3972fc 5f3972fc 50.00 0.02 0.58 1.00 20.04 17.28 35.10 19.12 19798.84 0.76 0.61 0.50
dcd1e104 dcd1e104 50.00 0.04 0.58 1.00 24.76 21.87 43.38 21.35 38001.68 0.00 0.00 0.00
8c8944b1 8c8944b1 50.00 0.06 0.58 1.00 12.32 14.54 21.10 18.45 20069.58 0.10 0.84 0.14
c6ab2f87 c6ab2f87 50.00 0.06 0.56 1.00 12.70 14.15 18.60 10.73 27507.32 0.14 0.90 0.35
37baec64 37baec64 50.00 0.08 0.54 1.00 15.14 17.95 15.86 10.48 15202.16 0.00 0.37 0.00
cdd73ca9 cdd73ca9 50.00 0.22 0.52 1.00 18.26 19.68 20.48 13.41 29056.02 0.00 0.27 0.46
509526f2 509526f2 50.00 0.06 0.50 1.00 27.20 23.96 38.44 22.41 29018.10 0.36 0.50 0.50
cbfef2dd cbfef2dd 50.00 0.10 0.50 1.00 17.18 20.19 10.12 3.21 24107.60 0.30 0.92 0.53
5355b9da 5355b9da 50.00 0.18 0.48 1.00 18.98 19.20 19.04 9.87 22428.48 0.14 0.80 0.38
0662f6a6 0662f6a6 50.00 0.02 0.48 1.00 20.40 25.83 17.62 16.23 18512.42 0.00 0.48 0.35
aed90615 aed90615 50.00 0.02 0.46 1.00 19.58 16.80 29.38 15.04 19121.20 0.03 0.83 0.50
94950854 94950854 50.00 0.06 0.46 1.00 17.46 18.87 22.40 17.42 21570.20 0.17 0.88 0.52
ae485d3e ae485d3e 46.00 0.02 0.46 1.00 17.83 15.99 28.07 16.89 27025.13 0.01 0.42 0.46
6d8bc8a8 6d8bc8a8 50.00 0.04 0.42 1.00 19.84 20.49 16.40 8.44 25511.06 0.00 1.00 0.51
ede87ff3 ede87ff3 50.00 0.02 0.40 1.00 16.74 18.80 14.54 7.74 39720.06 0.19 1.00 0.45
ede87ff3 ede87ff3 50.00 0.02 0.40 1.00 16.74 18.80 14.54 7.74 39720.06 0.19 1.00 0.45
d16c6455 d16c6455 50.00 0.02 0.38 1.00 27.16 22.55 27.42 21.90 32408.86 0.17 0.91 0.50
d5d714de d5d714de 47.00 0.02 0.36 1.00 29.51 25.07 26.00 10.12 27858.09 NA NA NA
bfb74651 bfb74651 50.00 0.02 0.32 1.00 26.10 22.34 18.54 11.60 16862.20 0.12 0.29 0.39
b6431c50 b6431c50 50.00 0.06 0.30 1.00 21.76 21.97 9.90 3.09 23196.82 0.15 0.76 0.57
9fccbd8e 9fccbd8e 50.00 0.04 0.26 1.00 21.82 21.93 6.54 4.26 40887.74 0.20 0.88 0.17
2528dac0 2528dac0 50.00 0.20 0.26 1.00 28.88 25.05 12.98 7.10 27617.72 0.24 0.78 0.51
1f77af01 1f77af01 50.00 0.00 0.26 1.00 42.72 27.88 31.10 23.75 13704.68 1.00 1.00 0.69
dbb2d209 dbb2d209 50.00 0.00 0.18 1.00 41.44 28.64 20.78 15.88 18154.66 0.14 0.69 0.33
eefdc883 eefdc883 50.00 0.02 0.16 1.00 31.00 22.35 10.72 3.40 16574.50 0.00 0.26 0.50
617ae74f 617ae74f 50.00 0.00 0.14 1.00 29.56 21.49 15.26 9.89 19565.26 0.16 0.40 0.50

Before we remove outliers, we want a look at how the data stack up (so when we throw away data we know what we’re losing):

From here on down we remove invalid responses and participants who over- and underperformed.

First we drop the 1 participants who didn’t do enough questions.

Next we drop the 0 participants who failed to provide at least 80% sensible answers (of whom 0 probably got ‘after’ and ‘before’ dates the wrong way around).

Having removed those, we then remove the 1 participants with hitrate > 2SD away from the population mean, because they probably looked up the answers (this is not a throwaway; individual answers have been checked and suggest a pattern).

Finally, we remove the 1 participants with a mean bracket width > 2SD away from the population mean because they’re not easily comparable with the others.

With those participants removed, we can provide some general information about performance based on the 30 participants who remain:

mean sd var
49.77 0.90 questionCount
0.07 0.07 hitRate
0.45 0.17 bracketRate
1.00 0.00 goodAnswerRate
21.15 8.22 meanError
20.35 3.72 sdError
20.40 8.34 meanBracketWidth
12.98 6.47 sdBracketWidth
25951.68 8467.54 meanRT
0.20 0.22 hard_easy
0.70 0.24 dull_fun
0.43 0.14 tooLong_tooShort

Having filtered out those who performed suspiciously, those who remain appear to have performed the task properly, getting few questions exactly right, answering almost all questions sensibly, and identifying the correct period approximately half the time.

Performance overview

Experiment feedback

## Warning: Removed 3 rows containing non-finite values (stat_ydensity).
## Warning: Removed 3 rows containing non-finite values (stat_boxplot).
## Warning: Removed 3 rows containing missing values (geom_point).

Difficulty rating vs hit/bracket rate

## Warning: Removed 1 rows containing non-finite values (stat_smooth).
## Warning: Removed 1 rows containing missing values (geom_point).

## Warning: Removed 1 rows containing non-finite values (stat_smooth).
## Warning: Removed 1 rows containing missing values (geom_point).

Further performance investigations

Bracket rate by bracket width

Performance by item

Sorted by bracketed %, decreasing.

qShort target topic n error.m error.sd timeA.m timeA.sd bracketed.m bracketed.sd bWidth.m bWidth.sd hit.m hit.sd
death of Elvis Presl death of Elvis Presl 1977.00 arts 8.00 2.00 1.69 23327.88 9942.66 1.00 0.00 11.88 8.66 0.25 0.46
meltdown at Chernoby meltdown at Chernoby 1986.00 technology 6.00 2.00 2.10 19325.33 3201.82 1.00 0.00 13.67 9.48 0.17 0.41
Harper Lee publishes Harper Lee publishes 1960.00 arts 8.00 8.62 7.56 17716.75 6543.02 0.88 0.35 18.12 8.43 0.12 0.35
John Lennon murdered John Lennon murdered 1980.00 arts 7.00 2.29 4.07 38340.86 37504.11 0.86 0.38 9.29 7.06 0.71 0.49
birth of Queen Eliza birth of Queen Eliza 1926.00 politics 13.00 4.08 4.29 28756.85 10586.82 0.85 0.38 14.00 8.62 0.08 0.28
Margaret Thatcher be Margaret Thatcher be 1979.00 politics 6.00 2.33 3.61 26726.67 16479.96 0.83 0.41 9.67 4.59 0.50 0.55
the Wright brothers the Wright brothers 1903.00 technology 6.00 7.17 5.74 23768.33 14151.53 0.83 0.41 20.17 8.38 0.00 0.00
Neil Armstrong becom Neil Armstrong becom 1969.00 science 11.00 8.64 17.73 33719.09 19096.65 0.82 0.40 15.55 25.99 0.36 0.50
Mike Tyson becomes t Mike Tyson becomes t 1986.00 sport 11.00 4.18 4.62 34572.64 26236.59 0.82 0.40 12.64 6.42 0.09 0.30
assassination of civ assassination of civ 1968.00 politics 10.00 7.60 8.29 56470.70 124802.00 0.80 0.42 14.60 7.85 0.10 0.32
Live Aid concert hel Live Aid concert hel 1985.00 arts 9.00 13.22 27.17 23451.67 14141.40 0.78 0.44 16.00 13.57 0.22 0.44
introduction of the introduction of the 1999.00 politics 8.00 12.00 19.52 24270.75 11185.91 0.75 0.46 14.12 24.83 0.38 0.52
nuclear bombs droppe nuclear bombs droppe 1945.00 military 8.00 10.00 16.41 24014.50 14870.55 0.75 0.46 9.12 9.25 0.25 0.46
168 people die in th 168 people die in th 1995.00 politics 8.00 29.00 33.38 45386.12 32642.58 0.75 0.46 35.38 43.46 0.00 0.00
first exhibition of first exhibition of 1999.00 arts 4.00 6.50 11.68 19456.25 3261.68 0.75 0.50 9.00 8.21 0.25 0.50
American Food and Dr American Food and Dr 1960.00 politics 4.00 16.00 8.98 38945.75 33402.65 0.75 0.50 30.00 16.33 0.00 0.00
discovery of Tutankh discovery of Tutankh 1922.00 science 4.00 20.75 13.43 39447.25 22901.99 0.75 0.50 46.25 38.16 0.00 0.00
assassination of US assassination of US 1963.00 politics 15.00 7.73 12.19 23427.80 13782.65 0.73 0.46 11.20 6.98 0.33 0.49
the first Mini autom the first Mini autom 1959.00 technology 11.00 17.00 19.52 32441.82 19923.37 0.73 0.47 25.73 20.07 0.00 0.00
Winston Churchill be Winston Churchill be 1940.00 politics 7.00 12.29 14.67 56614.86 53491.36 0.71 0.49 17.57 13.82 0.14 0.38
technology companies technology companies 1982.00 technology 7.00 7.00 6.24 32666.29 28412.07 0.71 0.49 11.86 6.12 0.00 0.00
King George VI dies King George VI dies 1952.00 politics 7.00 18.29 28.26 29716.86 14861.74 0.71 0.49 12.43 7.04 0.14 0.38
Germaine Greer publi Germaine Greer publi 1970.00 politics 7.00 11.14 10.82 25130.57 19120.29 0.71 0.49 17.29 18.90 0.29 0.49
break-in at the Demo break-in at the Demo 1972.00 politics 7.00 17.43 29.00 28278.00 10519.02 0.71 0.49 18.71 13.96 0.00 0.00
creation of the Nort creation of the Nort 1949.00 military 10.00 7.00 9.91 20245.90 7522.94 0.70 0.48 20.30 16.92 0.20 0.42
launch of the Hubble launch of the Hubble 1990.00 science 10.00 10.20 12.35 22911.60 10612.08 0.70 0.48 14.90 7.17 0.20 0.42
Chinese invasion of Chinese invasion of 1950.00 military 10.00 18.20 18.75 23268.30 10872.80 0.70 0.48 25.30 21.15 0.20 0.42
Sean Connery plays J Sean Connery plays J 1962.00 arts 10.00 9.80 9.57 21320.00 10349.38 0.70 0.48 17.40 8.49 0.00 0.00
first episode of Who first episode of Who 1998.00 arts 12.00 9.67 10.78 24816.33 13980.63 0.67 0.49 13.00 12.72 0.17 0.39
capture and executio capture and executio 1967.00 politics 9.00 12.89 22.78 24436.56 7039.97 0.67 0.50 18.11 10.75 0.11 0.33
World War I Armistic World War I Armistic 1918.00 military 9.00 9.00 21.82 26366.78 11758.90 0.67 0.50 6.33 5.61 0.33 0.50
Soviet cosmonaut Yur Soviet cosmonaut Yur 1961.00 science 9.00 8.33 10.98 25532.44 9790.85 0.67 0.50 17.67 12.96 0.11 0.33
Austrian bodybuilder Austrian bodybuilder 1965.00 sport 9.00 9.00 7.83 22215.44 10506.17 0.67 0.50 19.56 10.63 0.11 0.33
successful mammalian successful mammalian 1996.00 science 6.00 8.17 5.78 21635.50 11164.68 0.67 0.52 14.67 4.50 0.00 0.00
musical Cats opens i musical Cats opens i 1981.00 arts 3.00 6.33 4.51 21370.67 14088.54 0.67 0.58 13.33 5.77 0.00 0.00
the Soviet Union is the Soviet Union is 1991.00 politics 11.00 13.82 25.00 26526.45 11921.42 0.64 0.50 14.18 18.91 0.18 0.40
actress Marilyn Munr actress Marilyn Munr 1962.00 arts 11.00 8.64 9.95 29565.18 17175.71 0.64 0.50 15.64 12.31 0.18 0.40
apartheid begins in apartheid begins in 1948.00 politics 8.00 15.00 14.24 23521.88 13984.57 0.62 0.52 42.38 30.65 0.00 0.00
Diana, Princess of W Diana, Princess of W 1997.00 politics 8.00 11.75 21.10 25341.62 18359.57 0.62 0.52 14.25 13.33 0.12 0.35
the Arab Revolt begi the Arab Revolt begi 1916.00 military 8.00 20.12 18.00 17994.38 4648.98 0.62 0.52 26.25 13.02 0.00 0.00
Monty Python’s Flyin Monty Python’s Flyin 1969.00 arts 8.00 8.00 6.61 28864.00 16252.22 0.62 0.52 18.38 12.64 0.00 0.00
US-led coalition exp US-led coalition exp 1991.00 military 10.00 18.10 28.69 28247.70 19255.19 0.60 0.52 17.40 14.34 0.00 0.00
’Father of Psycholog ’Father of Psycholog 1910.00 science 10.00 26.40 23.09 23618.30 9508.69 0.60 0.52 26.30 18.32 0.00 0.00
penicillin discovere penicillin discovere 1928.00 science 10.00 15.10 11.14 25630.40 12498.55 0.60 0.52 26.60 11.79 0.00 0.00
the Wall Street cras the Wall Street cras 1929.00 politics 10.00 16.00 19.66 20392.30 9721.46 0.60 0.52 13.50 7.79 0.40 0.52
Space Shuttle Challe Space Shuttle Challe 1986.00 technology 10.00 7.40 7.37 28848.30 17893.54 0.60 0.52 13.50 10.41 0.10 0.32
Woodstock Music Fest Woodstock Music Fest 1969.00 arts 12.00 9.33 10.41 23064.50 15271.23 0.58 0.51 12.75 9.09 0.17 0.39
US poet Sylvia Plath US poet Sylvia Plath 1963.00 arts 14.00 18.50 16.36 21996.86 9918.70 0.57 0.51 32.07 33.32 0.07 0.27
Benito Mussolini fou Benito Mussolini fou 1921.00 politics 7.00 18.00 26.40 18967.00 9465.56 0.57 0.53 24.14 13.57 0.00 0.00
Emily Wilding Daviso Emily Wilding Daviso 1913.00 politics 7.00 27.14 29.45 23342.14 14353.18 0.57 0.53 22.00 11.60 0.14 0.38
the teddy bear is in the teddy bear is in 1903.00 technology 7.00 38.57 31.71 18817.43 12244.27 0.57 0.53 32.14 31.34 0.00 0.00
October Revolution i October Revolution i 1917.00 politics 7.00 22.14 26.39 19999.86 7260.70 0.57 0.53 17.71 27.91 0.29 0.49
Salman Rushdie publi Salman Rushdie publi 1988.00 arts 9.00 30.11 32.72 19171.33 10451.94 0.56 0.53 18.22 7.26 0.00 0.00
RMS Titanic begins h RMS Titanic begins h 1912.00 technology 11.00 14.09 24.36 17462.73 7547.38 0.55 0.52 14.45 15.12 0.36 0.50
first FIFA World Cup first FIFA World Cup 1930.00 sport 13.00 13.62 13.43 27257.85 14175.95 0.54 0.52 22.77 13.01 0.15 0.38
Ireland achieves ind Ireland achieves ind 1922.00 military 14.00 22.86 20.56 20833.43 9411.63 0.50 0.52 28.14 23.63 0.00 0.00
dissolution of the u dissolution of the u 1905.00 politics 12.00 35.08 30.43 21001.67 11501.18 0.50 0.52 33.25 23.83 0.00 0.00
foundation of Disney foundation of Disney 1923.00 technology 12.00 16.50 19.36 35493.67 51296.11 0.50 0.52 19.75 11.71 0.08 0.29
initiation of the Ma initiation of the Ma 1942.00 science 10.00 24.60 19.22 18739.40 7539.85 0.50 0.53 22.80 13.45 0.00 0.00
artist Frida Kahlo b artist Frida Kahlo b 1907.00 arts 10.00 14.80 15.75 26428.30 13551.55 0.50 0.53 24.20 12.55 0.00 0.00
partition of India i partition of India i 1947.00 politics 10.00 14.70 13.77 33460.90 25146.52 0.50 0.53 24.00 20.25 0.00 0.00
Egypt invaded by Isr Egypt invaded by Isr 1956.00 military 10.00 12.30 8.45 24728.60 11631.17 0.50 0.53 19.90 11.51 0.10 0.32
Mao Zedong establish Mao Zedong establish 1949.00 politics 8.00 14.75 16.95 23050.75 9667.30 0.50 0.53 32.00 33.42 0.12 0.35
up to 1 million peop up to 1 million peop 1994.00 military 8.00 33.62 30.39 29983.12 20938.35 0.50 0.53 28.12 33.80 0.00 0.00
W.B. Yeats awarded t W.B. Yeats awarded t 1923.00 arts 8.00 27.00 25.12 24913.88 18975.70 0.50 0.53 34.88 22.81 0.00 0.00
Virginia Wolfe publi Virginia Wolfe publi 1925.00 arts 8.00 26.12 26.59 17658.25 17083.37 0.50 0.53 18.00 7.69 0.00 0.00
Triangle Shirtwaist Triangle Shirtwaist 1911.00 politics 8.00 18.25 23.66 19093.75 9115.40 0.50 0.53 17.50 15.59 0.00 0.00
Port Arthur, Canada Port Arthur, Canada 1908.00 politics 8.00 32.50 28.75 20324.50 8951.40 0.50 0.53 20.62 13.31 0.12 0.35
Maya Angelou publish Maya Angelou publish 1969.00 arts 8.00 17.38 17.41 24835.25 17833.32 0.50 0.53 27.50 12.54 0.00 0.00
the Russian Social D the Russian Social D 1903.00 politics 6.00 18.33 12.48 22682.83 15610.21 0.50 0.55 25.83 19.25 0.00 0.00
maiden flight of Con maiden flight of Con 1969.00 technology 6.00 8.50 9.48 27046.83 17347.63 0.50 0.55 10.83 5.85 0.33 0.52
Japanese invasion of Japanese invasion of 1937.00 military 6.00 11.33 9.48 24290.00 13727.92 0.50 0.55 17.83 10.40 0.00 0.00
Frigidaire begins se Frigidaire begins se 1923.00 technology 6.00 10.00 7.80 28900.67 20581.46 0.50 0.55 26.67 13.66 0.00 0.00
Steven Spielberg dir Steven Spielberg dir 1993.00 arts 6.00 5.17 4.36 20349.50 8958.97 0.50 0.55 12.83 5.71 0.17 0.41
Israel established a Israel established a 1948.00 politics 4.00 11.25 7.80 44767.25 24211.13 0.50 0.58 19.25 15.78 0.00 0.00
Britain and Argentin Britain and Argentin 1982.00 military 4.00 29.25 39.38 28828.00 8246.92 0.50 0.58 23.00 24.99 0.00 0.00
Saigon (now Ho Chi M Saigon (now Ho Chi M 1975.00 military 11.00 13.27 12.43 28827.73 9025.00 0.45 0.52 18.91 18.07 0.09 0.30
Civil Rights Act out Civil Rights Act out 1964.00 politics 11.00 19.27 22.09 16225.36 5573.65 0.45 0.52 14.55 8.34 0.00 0.00
Human Immunodeficien Human Immunodeficien 1983.00 science 11.00 11.73 17.50 18762.73 6244.93 0.45 0.52 14.55 7.34 0.00 0.00
RMS Lusitania sunk b RMS Lusitania sunk b 1915.00 military 11.00 20.64 17.96 30384.09 16615.79 0.45 0.52 13.27 13.32 0.09 0.30
James Joyce’s Ulysse James Joyce’s Ulysse 1922.00 arts 11.00 29.18 25.38 18761.45 8936.86 0.45 0.52 38.91 33.12 0.00 0.00
King George VI gives King George VI gives 1932.00 politics 9.00 18.44 14.88 22233.00 7454.26 0.44 0.53 25.00 16.20 0.00 0.00
Tunguska event flatt Tunguska event flatt 1908.00 science 9.00 39.11 32.79 21755.00 17751.35 0.44 0.53 34.44 23.38 0.00 0.00
public prosecution o public prosecution o 1960.00 arts 9.00 17.67 17.90 21781.33 10537.29 0.44 0.53 24.89 16.47 0.22 0.44
riots in Los Angeles riots in Los Angeles 1992.00 politics 9.00 18.78 23.06 36056.67 15747.25 0.44 0.53 11.33 14.83 0.00 0.00
synthetic polymer ny synthetic polymer ny 1938.00 technology 16.00 22.94 17.85 22127.44 13742.32 0.44 0.51 26.62 17.64 0.00 0.00
the Turkish Republic the Turkish Republic 1924.00 politics 7.00 27.57 24.95 19951.71 13501.45 0.43 0.53 32.86 18.68 0.00 0.00
Pluto discovered by Pluto discovered by 1930.00 science 7.00 18.86 19.94 16146.43 5634.75 0.43 0.53 36.43 33.75 0.14 0.38
Cuban Missile Crisis Cuban Missile Crisis 1962.00 military 7.00 20.57 27.51 38089.86 44743.06 0.43 0.53 14.43 12.09 0.29 0.49
Joseph Stalin’s Grea Joseph Stalin’s Grea 1936.00 politics 7.00 10.71 7.23 26654.00 11275.10 0.43 0.53 15.00 7.81 0.00 0.00
opening of the Chann opening of the Chann 1994.00 technology 7.00 20.00 21.60 19278.43 13544.04 0.43 0.53 16.57 9.25 0.14 0.38
end of British rule end of British rule 1997.00 politics 12.00 29.17 29.08 23527.50 15567.23 0.42 0.51 18.08 14.63 0.17 0.39
Spanish Civil War be Spanish Civil War be 1936.00 military 15.00 20.60 15.45 18428.47 7793.14 0.40 0.51 24.00 16.12 0.13 0.35
Steffi Graf becomes Steffi Graf becomes 1987.00 sport 10.00 13.30 8.50 32917.00 22494.92 0.40 0.52 17.40 12.64 0.00 0.00
ballet dancer Mikhai ballet dancer Mikhai 1974.00 arts 10.00 14.90 14.92 22253.90 8062.22 0.40 0.52 18.00 15.13 0.00 0.00
the zeppelin Hindenb the zeppelin Hindenb 1937.00 technology 10.00 15.50 8.55 23408.10 5960.88 0.40 0.52 21.20 8.70 0.00 0.00
Orson Welles’ Citize Orson Welles’ Citize 1941.00 arts 5.00 17.40 19.71 33136.20 16876.47 0.40 0.55 22.40 14.10 0.00 0.00
first moving assembl first moving assembl 1913.00 technology 5.00 20.60 25.74 17799.80 8887.11 0.40 0.55 16.00 5.48 0.20 0.45
first Disneyland ope first Disneyland ope 1955.00 technology 5.00 15.40 10.53 47075.80 47249.61 0.40 0.55 16.60 18.84 0.00 0.00
first link establish first link establish 1969.00 technology 8.00 11.12 6.77 22739.50 12510.60 0.38 0.52 23.38 12.18 0.00 0.00
Edmund Hillary and T Edmund Hillary and T 1953.00 sport 8.00 18.12 11.15 27264.50 12464.19 0.38 0.52 23.88 13.39 0.00 0.00
Charles de Gaulle el Charles de Gaulle el 1958.00 politics 8.00 18.00 12.80 20250.62 8342.88 0.38 0.52 20.62 18.86 0.00 0.00
foundation of the Mu foundation of the Mu 1928.00 politics 8.00 30.75 25.68 30809.62 18596.88 0.38 0.52 24.38 20.08 0.12 0.35
birth of Louise Brow birth of Louise Brow 1978.00 technology 8.00 11.75 15.24 30518.12 22542.03 0.38 0.52 20.00 14.88 0.00 0.00
death of Martha, the death of Martha, the 1914.00 science 8.00 28.12 29.63 37954.38 20118.62 0.38 0.52 22.50 14.88 0.12 0.35
Mahatma Gandhi’s fir Mahatma Gandhi’s fir 1920.00 politics 11.00 39.82 19.15 31201.55 24792.56 0.36 0.50 33.00 20.66 0.00 0.00
creation of the Cent creation of the Cent 1947.00 politics 11.00 15.64 15.60 16818.73 6301.26 0.36 0.50 18.91 10.24 0.00 0.00
Britain replaces pou Britain replaces pou 1971.00 technology 12.00 20.75 18.31 25479.50 18460.96 0.33 0.49 15.67 4.12 0.00 0.00
high school teacher high school teacher 1925.00 politics 12.00 33.92 20.32 25329.00 17473.21 0.33 0.49 24.50 14.02 0.00 0.00
Guglielmo Marconi re Guglielmo Marconi re 1901.00 technology 9.00 16.56 14.96 20742.00 9015.52 0.33 0.50 23.89 16.35 0.11 0.33
premier of John Cage premier of John Cage 1952.00 arts 9.00 26.44 15.16 26359.89 23871.34 0.33 0.50 23.44 29.61 0.00 0.00
the Chinese Empire e the Chinese Empire e 1912.00 politics 9.00 22.78 14.54 28900.67 17147.89 0.33 0.50 21.11 15.96 0.11 0.33
Steve Jobs and Steve Steve Jobs and Steve 1976.00 technology 9.00 9.11 6.86 25071.89 16581.29 0.33 0.50 13.44 10.15 0.00 0.00
Germany enacts the N Germany enacts the N 1935.00 politics 9.00 19.56 16.87 30779.33 28730.89 0.33 0.50 16.44 13.13 0.00 0.00
George Orwell publis George Orwell publis 1949.00 arts 9.00 14.11 7.99 25695.44 12433.28 0.33 0.50 22.89 11.10 0.00 0.00
US Supreme Court rul US Supreme Court rul 1973.00 politics 9.00 15.33 12.22 24111.33 15139.28 0.33 0.50 24.67 27.19 0.00 0.00
Panama Canal opens Panama Canal opens 1914.00 technology 6.00 36.50 27.49 13402.67 5689.07 0.33 0.52 26.67 19.66 0.00 0.00
George Nissen and La George Nissen and La 1936.00 sport 6.00 29.17 16.29 15946.17 7068.56 0.33 0.52 30.00 16.43 0.00 0.00
prohibition abolishe prohibition abolishe 1933.00 politics 6.00 21.17 18.90 14489.67 3952.28 0.33 0.52 18.83 8.84 0.17 0.41
George Gershwin’s Rh George Gershwin’s Rh 1924.00 arts 6.00 25.50 15.19 21411.83 7385.21 0.33 0.52 23.00 10.26 0.00 0.00
J.D. Salinger publis J.D. Salinger publis 1951.00 arts 6.00 19.33 8.41 20190.00 11888.07 0.33 0.52 20.83 14.97 0.00 0.00
first The Wizard of first The Wizard of 1902.00 arts 6.00 32.33 33.48 20012.33 11776.17 0.33 0.52 17.50 6.12 0.00 0.00
the Flying Scotsman the Flying Scotsman 1934.00 technology 6.00 20.67 10.88 28329.50 13322.07 0.33 0.52 28.33 21.13 0.00 0.00
Igor Stravinsky’s ba Igor Stravinsky’s ba 1913.00 arts 13.00 38.62 27.02 19372.62 8118.65 0.31 0.48 21.77 9.20 0.00 0.00
Roger Bannister runs Roger Bannister runs 1954.00 sport 10.00 16.50 14.68 29969.30 24297.83 0.30 0.48 15.10 8.03 0.00 0.00
sisters Laura Richar sisters Laura Richar 1917.00 arts 10.00 40.70 25.05 19776.50 11631.88 0.30 0.48 26.30 9.72 0.00 0.00
first Tour de France first Tour de France 1903.00 sport 10.00 53.60 32.15 19943.90 7235.37 0.30 0.48 21.00 21.69 0.00 0.00
draughtsman Harry Be draughtsman Harry Be 1931.00 technology 14.00 29.21 20.73 24705.86 15623.77 0.29 0.47 25.57 11.81 0.00 0.00
British Commonwealth British Commonwealth 1931.00 politics 7.00 29.00 15.35 18407.43 7205.13 0.29 0.49 30.71 31.01 0.00 0.00
Albert Einstein publ Albert Einstein publ 1905.00 science 7.00 29.43 24.85 36148.86 32358.56 0.29 0.49 19.29 12.72 0.00 0.00
Douglas Adams’ The H Douglas Adams’ The H 1978.00 arts 7.00 13.86 11.96 27420.00 25147.60 0.29 0.49 16.29 11.10 0.00 0.00
Andrew Wiles publish Andrew Wiles publish 1995.00 science 7.00 54.00 36.38 23956.43 15418.75 0.29 0.49 51.57 35.77 0.00 0.00
the Bureau of Invest the Bureau of Invest 1908.00 politics 11.00 36.73 33.86 28207.82 17644.06 0.27 0.47 18.09 12.16 0.00 0.00
Eugene Burton Ely pe Eugene Burton Ely pe 1911.00 technology 11.00 39.27 29.69 21075.82 8688.67 0.27 0.47 21.45 15.27 0.00 0.00
the Federal Reserve the Federal Reserve 1913.00 politics 11.00 32.09 26.69 34464.27 21769.01 0.27 0.47 20.82 13.20 0.00 0.00
World Health Organis World Health Organis 1948.00 politics 11.00 20.36 13.77 16167.18 9878.54 0.27 0.47 13.82 6.11 0.09 0.30
thousands of protest thousands of protest 1989.00 politics 8.00 34.00 16.69 16004.75 7005.03 0.25 0.46 20.62 8.63 0.00 0.00
murder of Russian my murder of Russian my 1916.00 politics 8.00 39.50 32.13 21243.62 14103.49 0.25 0.46 21.88 14.14 0.00 0.00
oldest known cave pa oldest known cave pa 1994.00 arts 13.00 48.92 30.08 27445.31 18496.55 0.23 0.44 30.08 21.52 0.00 0.00
Emily Hobhouse deliv Emily Hobhouse deliv 1901.00 politics 9.00 37.56 34.85 29518.22 17263.99 0.22 0.44 18.56 12.40 0.00 0.00
Roald Amundsen reach Roald Amundsen reach 1911.00 science 9.00 25.67 28.54 27974.44 19716.99 0.22 0.44 18.00 10.27 0.22 0.44
Willis Carrier inven Willis Carrier inven 1902.00 technology 9.00 41.00 25.32 32225.00 21424.21 0.22 0.44 20.78 12.89 0.00 0.00
Tim Berners-Lee publ Tim Berners-Lee publ 1991.00 technology 9.00 8.56 5.66 35437.78 42295.27 0.22 0.44 11.89 7.61 0.00 0.00
The USA officially a The USA officially a 1931.00 arts 10.00 21.50 18.67 56028.30 92391.79 0.20 0.42 23.90 16.80 0.00 0.00
last two judicial ex last two judicial ex 1964.00 politics 10.00 29.00 24.17 25790.60 11581.32 0.20 0.42 23.30 10.25 0.00 0.00
the Velvet Revolutio the Velvet Revolutio 1989.00 politics 5.00 39.00 38.94 28506.40 13881.33 0.20 0.45 30.20 19.31 0.00 0.00
Augusto Pinochet beg Augusto Pinochet beg 1973.00 politics 5.00 17.40 9.66 22554.80 8830.86 0.20 0.45 12.40 4.51 0.00 0.00
Janet Gaynor wins ’B Janet Gaynor wins ’B 1929.00 arts 11.00 31.36 18.73 15772.09 6417.67 0.18 0.40 25.00 9.22 0.00 0.00
Jack Kerouac publish Jack Kerouac publish 1957.00 arts 11.00 21.91 12.19 14203.55 8083.20 0.18 0.40 18.18 8.45 0.00 0.00
the Hoover Dam is co the Hoover Dam is co 1936.00 technology 11.00 17.82 12.70 28138.64 42378.31 0.18 0.40 19.27 13.22 0.00 0.00
Charlie Chaplin’s Th Charlie Chaplin’s Th 1940.00 arts 6.00 20.50 13.32 16870.33 10235.75 0.17 0.41 17.33 2.94 0.00 0.00
Nancy Astor, Viscoun Nancy Astor, Viscoun 1919.00 politics 6.00 32.33 22.51 18004.50 4025.25 0.17 0.41 15.00 8.94 0.00 0.00
Colossus, the first Colossus, the first 1944.00 technology 6.00 21.00 14.83 21577.50 10527.89 0.17 0.41 17.17 15.14 0.00 0.00
Stonewall riots in N Stonewall riots in N 1969.00 politics 7.00 15.43 10.28 22890.86 14471.67 0.14 0.38 17.43 7.61 0.00 0.00
first photograph of first photograph of 1946.00 technology 8.00 20.62 9.96 22846.00 9385.50 0.12 0.35 19.75 9.48 0.00 0.00
Thalidomide is withd Thalidomide is withd 1961.00 science 9.00 24.56 20.38 24967.67 18703.17 0.11 0.33 17.22 15.63 0.00 0.00
first photographs of first photographs of 1910.00 science 9.00 50.67 29.58 21421.00 13542.52 0.11 0.33 14.00 8.89 0.00 0.00
Estonia wins indepen Estonia wins indepen 1920.00 military 11.00 58.00 20.92 38600.82 48608.79 0.09 0.30 16.09 9.53 0.00 0.00
Chuck Yeager officia Chuck Yeager officia 1947.00 technology 12.00 29.50 11.48 23610.75 12360.92 0.08 0.29 17.00 11.03 0.00 0.00
inaugural elections inaugural elections 1906.00 politics 10.00 50.70 27.04 25631.50 16409.99 0.00 0.00 20.70 10.92 0.00 0.00
Simone de Beauvoir p Simone de Beauvoir p 1949.00 arts 9.00 29.00 11.58 16411.33 6963.07 0.00 0.00 19.22 15.13 0.00 0.00
Henry Dunant, founde Henry Dunant, founde 1901.00 politics 8.00 48.25 28.18 22094.88 16081.14 0.00 0.00 21.25 13.82 0.00 0.00
foundation of the So foundation of the So 1912.00 politics 6.00 47.00 19.92 35760.00 24227.27 0.00 0.00 20.83 20.10 0.00 0.00
144 people die in Ab 144 people die in Ab 1966.00 politics 5.00 34.60 18.37 27803.00 12826.78 0.00 0.00 15.40 4.56 0.00 0.00
the Lateran Treaty e the Lateran Treaty e 1929.00 politics 5.00 28.20 5.22 28090.80 26955.16 0.00 0.00 14.40 16.33 0.00 0.00
creation of the Brit creation of the Brit 1927.00 politics 4.00 41.75 24.51 13013.25 6962.02 0.00 0.00 15.00 5.77 0.00 0.00

(This might look better rotated through 90 degrees)

Do items get easier as they get more recent?

Individual item plots